Genesis 21:1-7 NIV

[1] Now the LORD was gracious to Sarah as he had said, and the LORD did for Sarah what he had promised. [2] Sarah became pregnant and bore a son to Abraham in his old age, at the very time God had promised him. [3] Abraham gave the name Isaac to the son Sarah bore him. [4] When his son Isaac was eight days old, Abraham circumcised him, as God commanded him. [5] Abraham was a hundred years old when his son Isaac was born to him. [6] Sarah said, “God has brought me laughter, and everyone who hears about this will laugh with me.” [7] And she added, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.”